The present invention concerns a method and a device for manufacturing three dimensional bodies of a great number of mutually connected layers of a particle shaped material, such as a powder, and where the information of the appearance of each layer is achieved from a computer""s CAD-unit or similar.
Manufacturing of prototypes from originals in A form of separate CAD-drawings, where the information from each layer is used for stiffening or melting together material for a three dimensional body, is known. U.S. Pat. No. 4,575,330 describes the use of a UV-laser beam for hardening (stiffening) the surface layer in a reservoir with liquid plastic (photopolymer). In order to be able to build details with thin walls and with high precision, the focus point (diameter) of the laser is minimized to fractions of 1 millimeter. The laser beam must illuminate all surfaces, which shall become solid. That takes a long time to produce a detail.
EP-A2 470 705 describes a three dimensional modeling, where the speed has been increased by illuminating the whole surface at one time with a large UV-lamp. The UV-light is shielded with toner from a laser printer on a glass plate. In order to manage details with overhang a support structure is built with the aid of wax, which solidify.
The drawbacks with reactive liquid plastics are that they are dangerous for personnel and for the environment, and that variations of different qualities are limited.
In order to avoid this and the use of a support structure, a plastic or wax powder is used, where the unsintered powder bakes in the proceeding layers and in this way supports possible xe2x80x9coverhangxe2x80x9d; such as when a hat on a mushrom is made. These machines, e.g. from the German firm EOS GmbH and the US-firm DTM Inc. use a controllable laser beam to selectively melt the powder. In order to increase the speed, one heats the powder reservoir to a temperature just below the melting point of the powder and let the laser beam increase the temperature to the degrees that are necessary for melting/sintering together the powder. It will take 10-20 hours to manufacture a prototype detail of normal size. Machines based on laser or UV technique are very expensive to buy. The costs are in the order of 3-6 million SEK.
The purpose with the present invention is to eliminate the above-mentioned drawbacks and to achieve:
three dimensional bodies, also such with thin walls and with high precision
articles with overhang without the aid of support structures
a method which is not dangerous for personnel and for the environment
large qualitative possibilities of variations
a simple, inexpensive and reliable machine equipment
fast manufacturing of three dimensional bodies
These objects have been achieved by the steps by applying an even particle layer on a support surface, a masking device that is arranged to provide a masking pattern in accordance with the information from the CAD-unit. The masking device is led over the particle layer. A radiation producer is arranged or is led over the masking device, whereby the particles, which are not covered by the masking pattern, are exposed to radiation and thereby are attached to each other. The masking pattern is removed from the masking device and that new sequences in accordance with the above are carried through until the three dimensional body is produced.